Some are also organising sex tours over the internet, before travelling to Asian countries to abuse children.

Details are necessarily sketchy - to avoid tipping off abusers - but Fairfax can reveal that the Australian Federal Police, Customs, the Australian Crime Commission and state police are targeting the perverts with a recently launched operation called Osman.

Detective Senior Sergeant Rob Ridley, head of the Victoria Police Astraea taskforce, which works with other agencies to tackle online child abuse, said the operation was conceived when authorities realised paedophiles were exploiting the internet in new ways.

''There's what people have traditionally thought of as the travelling sex offender that goes overseas to have sex with children, but now he's making the preparations here,'' he said. ''There's both federal and state legislation that can cover those acts of preparation. Our emphasis is obviously to disrupt and prevent; for obvious reasons we can't let them go over and offend.

''Then there's the more recent way they operate, which is similar to the live sex shows that happen in the adult sex industry, which has now spilled over into child sex offending, where people online order certain types of offending against children, particularly in south-east Asian countries, but there have been some reports of it happening in Europe as well.''

Although police would not identify individual countries being targeted by paedophiles - because there might be continuing investigations linked to those countries - the federal police told Fairfax earlier this year that an investigation had uncovered ''webcam'' child abuse in the Philippines.

''In the Philippines, households - mum and dad - have now got their eight-year-old daughter or son in a room on a video camera, and there are Australians telling mum and dad what to get the child to do,'' Assistant Commissioner Kevin Zuccato said.

''What you're seeing is an evolution of that type of crime, and when you extrapolate that to other types of crime, it's a big issue.''

Federal police say they work closely with overseas counterparts to ensure paedophiles managing to leave Australia are turned back before entering the country where they intend abusing a child. They also work to ensure children offered to Australians abusers are rescued by local authorities.

''Child sexual exploitation and abuse is not just a law enforcement issue,'' an AFP spokeswoman said. ''The victims are children, our children. We … call on the public to remain vigilant and report any suspicious activity.''